The present invention relates to a novel thickening system (agent), a composition in aqueous medium, comprising the novel thickening system, and the use of this novel thickening system in a composition in aqueous medium, in particular in the cosmetics field.
It is known to use, as an agent for thickening aqueous media, water-soluble or water-dispersible polymers, and in particular polymers which may be crosslinked. The thickening is then brought about by interlinking of the polymer chains, the polymers preferably having a long chain length and a high molecular weight.
It is also known to use, as a thickener for aqueous media, hydrophilic polymers containing hydrophobic groups, in the form of sequences, grafts and/or side groups distributed randomly. These polymers allow considerable thickening of the medium to be obtained even when they are used in small amounts. The thickening is generated by the formation of aggregates between the hydrophobic groups of the polymer, these aggregates constituting physical crosslinking points between the macromolecular chains.
However, it has been observed that the presence of hydrophilic polymers containing hydrophobic groups, even in small amounts, in compositions, especially cosmetic compositions, could adversely modify the cosmetic properties of the compositions, for example the feel or spreading properties.
It is also known to prepare hair compositions in gel form comprising polymers containing hydrophobic groups combined with surfactants; the gel is then formed by means of the formation of mixed micelles. However, it has been observed that the texture obtained often has a tendency to break, which makes the composition difficult to handle. Furthermore, the presence of an excess of surfactant could lead to certain drawbacks in the field of leave-in compositions.
Thus, there is a need for a thickening system which makes it possible to thicken, or even to gel, a composition comprising an aqueous medium, without having any influence on the cosmetic properties of the compositions.
The aim of the present invention is to propose such a thickening system which also allows adequate thickening to be obtained using a very small amount of thickening polymer.
One subject of the present invention is thus a composition in aqueous medium, comprising the combination of at least one amphiphilic polymer comprising at least one fatty chain and at least one hydrophilic unit, and of at least one protein including at least one hydrophobic group, wherein the protein is not the same as the amphiphilic polymer.
Another subject of the invention is the use, in particular in a composition in aqueous medium, of the combination of at least one protein including at least one hydrophobic group and of at least one amphiphilic polymer which contains at least one fatty chain and at least one hydrophilic unit, as a thickening agent, wherein, of course, the protein is different from the amphiphilic polymer.
Yet another subject of the invention is a process for thickening a composition in aqueous medium, in which at least one protein including at least one hydrophobic group and at least one amphiphilic polymer comprising at least one fatty chain and at least one hydrophilic unit are added to the composition, wherein the protein and the amphiphilic polymer are not the same.
Another subject of the invention is the use of at least one protein including at least one hydrophobic group in order to improve the thickening power of an amphiphilic polymer comprising at least one fatty chain and at least one hydrophilic unit.
It has thus been observed that such a combination makes it possible to obtain, in aqueous medium, a large increase in viscosity which can go as far as total gelation of the medium.
It is thus possible to achieve thickening, or even gelation, using smaller amounts of polymer, while at the same time retaining good cosmetic properties. It should be noted that the polymer alone, in the amounts at which it is used in the presence of protein, would not necessarily allow the medium to be thickened.
The protein/polymer interaction thus makes it very easy to control the degree of viscosity of the medium by simple mixing, in proportions which may be adjusted at will, two fluid solutions, namely an aqueous polymer solution and an aqueous protein solution.
One advantage of the invention lies in the fact that it is possible to obtain suitable thickening of the medium while at the same time providing certain skin care and/or skin treatment properties by appropriately selecting the protein.
Thus, it may be envisaged that the composition according to the present invention will:
provide moisturizing effects, when the protein possesses these effects;
provide a skin-regenerating effect, by supplying amino acids and proteins;
provide a mild bactericidal effect, by using certain proteins such as lysozyme;
provide anti-free-radical effects, by using proteins such as superoxide dismutases.
Furthermore, the polymer network may have a certain protective effect towards the protein, in particular with respect to denaturing agents such as temperature or acidity, this being particularly advantageous when the protein is an enzyme.
Moreover, the cosmetic composition obtained, and in particular one which is a hair composition, can spread easily, can have good handling properties, and can be eliminated well on rinsing.
Without being limited by this explanation, it may be considered that, within the context of the invention, the increase in viscosity of the medium may result from physical crosslinking between the polymer chains and the protein, the crosslinking being reversible and involving associations or interactions of hydrophobic type between, on the one hand, the hydrophobic groups of the polymer and, on the other hand, the hydrophobic sites of the protein.
These hydrophobic-type interactions can then lead to the gelation network.
Depending on the type of protein used, the hydrophobic sites of the protein may be found at the surface of the protein (globular or fibrous proteins, for example) or may be distributed throughout the protein chain (proteins of unordered structure, for example).
The polymers which can be used in the present invention are preferably amphiphilic polymers which contain at least one fatty chain, and thus a hydrophobic part, and at least one hydrophilic unit, and thus a hydrophilic part.
The hydrophobic part may be small in number relative to the rest of the polymer chain, and may be located laterally on the chain and distributed randomly (random copolymers) or distributed in the form of sequences or grafts (block copolymers or sequenced copolymers).
Water-soluble or water-dispersible polymers may be used.
Polymers which xe2x80x9cswellxe2x80x9d in water may also be used, in particular when the copolymer is partially crosslinked.
The polymers may be of any chemical nature; it is thus possible to select natural polymers, which may be modified; radical polymers, in particular vinyl or acrylic radical polymers; polycondensates; and mixtures thereof.
They can be preferably ionic or nonionic and are more preferably anionic or nonionic.
Among the polymers according to the invention of derived natural type, mention may be made in particular of:
cellulose ethers possessing hydrophobic substituents, which may be alkyl groups having more than 8 carbons.
Hydroxyethylcellulose substituted with hydrophobic groups may be mentioned. Among the commercial products used in the cosmetic field, mention may be made of Natrosol Plus Grade 330 sold by the company Aqualon.
quaternized cationic celluloses modified with groups containing at least one fatty chain, such as alkyl, arylalkyl or alkylaryl groups or mixtures thereof, in which the alkyl groups are preferably C8-C22;
quaternized alkylhydroxyethylcelluloses (cationic) such as the products Quatrisoft LM 200, Quatrisoft LM-X 529-18-A, Quatrisoft LM-X 529-18-B (C12 alkyl) and Quatrisoft LM-X 529-8 (C18 alkyl) sold by the company Amerchol and the products Crodacel QM, Crodacel QL (C12 alkyl) and Crodacel QS (C18 alkyl) sold by the company Croda;
galactomannans possessing hydrophobic substituents, and in particular hydrophobic substituted guar gum. Some of these derivatives are described in particular in EP 281,360, the disclosure of which is specifically incorporated by reference herein.
pullulans modified with hydrophobic groups, in particular cholesterol groups.
gelatins modified with hydrophobic groups, and in particular modified with C6 to C18 alkyl groups.
mucopolysaccharides such as those made of glycosaminoglycan and hyaluronic acid.
Among the polycondensates which can be used in the context of the invention, mention may be made of associative polyurethanes which are nonionic sequenced copolymers including, in the chain, both hydrophilic sequences, usually of polyoxyethylene nature, and hydrophobic sequences, which may be aliphatic chain units alone and/or cycloaliphatic and/or aromatic chain units.
The resulting sequenced copolymers may preferably be of the triblock or multiblock type. The hydrophobic sequences may thus be at each end of the chain (triblock copolymers with a central polyoxyethylene sequence) or distributed simultaneously at the ends and in the chain (multisequenced copolymers). They may also be as grafts or as a star.
Mention may be made of the polymers described in the article by ZEYING MA, J. of Appl. Polymer Sci., Vol. 49, 1509-27 (1993), the disclosure of which is specifically incorporated by reference herein.
Among the commercial polymers, those which may be mentioned are SER-AD FX1100 and SER-AD FX1035 from Hxc3xcls.
Among the radical polymers according to the invention, those which may be mentioned are anionic acrylic polymers, in aqueous dispersion, generally referred to as HASE (hydrophobically modified alkali-soluble or swellable emulsion). These are acrylic copolymers which exist in the form of dispersions in water at acidic pH and which may be dissolved in water by complete neutralization of the anionic groups, that is to say above pH 8.
Some of these dispersions may preferably be partially crosslinked. This requires that the complete neutralization should not bring about the complete solubilization of the polymer particles, but should give rise to strong swelling of these particles, also leading to gelation of the medium.
These non-crosslinked or partially crosslinked copolymers are preferably terpolymers between a monomer bearing a carboxylic acid group (acrylic acid, methacrylic acid), a relatively water-insoluble monomer of the C1 to C4 acrylate or methacrylate type, such as ethyl acrylate, and a third monomer bearing a hydrophobic group, which may be attached laterally to the main chain.
This hydrophobic group may preferably be a linear or branched alkyl group and/or a cycloalkyl group and/or an aryl group. The hydrophobic group may preferably be attached to the main chain directly via an ether, ester, or amide, carbamate or urea bond. It may also preferably be attached to the main chain via a polyoxyethylenated sequence, which is itself fixed onto the chain by an ether, ester, amide, carbamate or urea bond. In the latter case, the side groups are preferably small grafts containing hydrophilic and hydrophobic sequences, and the properties of thickening aqueous media are of higher performance.
Such aqueous polymer dispersions are described in particular in Shay, Surface Coatings International, 1993 (11) 446-453, and in U.S. Pat. No. 4,421,902, U.S. Pat. No. 4,423,199 and U.S. Pat. No. 4,663,385 from Rxc3x6hm and Haas and U.S. Pat. No. 4,384,096 from Dow Corning, the disclosures of which are specifically incorporated by reference herein.
Mention may also be made of the products Acusol 823 and Acrysol 25 or 22 from Rxc3x6hm and Haas.
Among the radical polymers according to the invention, those which may also be mentioned are:
copolymers of acrylic acid or methacrylic acid with N-alkylacrylamides, and in particular copolymers of acrylic acid/N-alkylacrylamides having a C1 to C20 alkyl group, such as those described in the article Magny et al., Double Liaison, 451, pp. 52-55 (1993), the disclosure of which is specifically incorporated by reference herein. They may be obtained by direct copolymerization or by subsequent amidation of the acrylic acid chain.
Depending on the procedure used, the hydrophobic alkyl groups may be distributed randomly (amidation in homogeneous organic solution) or in sequenced form (amidation in aqueous medium where the amine initially forms aggregates of micelle type).
other anionic radical copolymers, such as copolymers between a monomer containing a carboxylic acid group, for example (meth)acrylic acid, and (meth)acrylate esters or amides bearing hydrophobic cycloaliphatic or aromatic groups, such as isobornyl or adamantyl groups.
Mention may also be made of copolymers with perfluoro monomers, in particular copolymers with perfluorohexyl (meth)acrylate; copolymers between a monomer bearing a sulphonic acid group (in particular 2-acrylamido-2-methyl-2-propanesulphonic acid, styrenesulphonic acid) and an alkyl (meth)acrylamide possessing at least 8 carbons.
nonionic acrylic copolymers, and in particular copolymers of acrylamide/N-alkylacrylamide type such as those described in Goodwin et al., Polymer in Aqueous Media=Performance Through Association, (J. E. Glassed) Adv. Chem. Ser. 223; Am. Chem. Soc., Washington D.C., p. 365 (1989), the disclosure of which is specifically incorporated by reference herein.
Mention may also be made of:
copolymers of maleic anhydride and of monomers including at least one fatty chain, such as N-octadecyl vinyl ether/maleic anhydride copolymers, for instance the product Gantrez AN-8194 sold by the company ISP;
copolymers of crotonic acid and of monomers including at least one fatty chain, such as vinyl acetateicrotonic acidivinyl neodecanoate terpolymers, for instance the product Resine 28-2930 sold by the company National Starch; or vinyl acetate/crotonic acid/allyl stearate terpolymers such as the products Mexomere PV and PB sold by the company Chimex;
(meth)acrylic acid polymers modified with groups including at least one fatty chain or copolymers of (meth)acrylic acid and of monomers including at least one fatty chain; these monomers are preferably chosen from hydrophobic monomers including a fatty chain, amphiphilic monomers including a hydrophobic part with a fatty chain and a hydrophilic part, or mixtures thereof. Mention may be made, by way of example, of:
crosslinked copolymers of acrylic acid/C10-C30 alkyl acrylate such as the products Pemulen TR 1, Pemulen TR 2, Carbopol 1382, Carbopol 1342 and Carbopol ETD 2020 sold by the company Goodrich;
(meth)acrylic acid/ethyl acrylate/alkyl acrylate copolymers such as the product Acusol 823 sold by the company Rxc3x6hm and Haas and the product Imperon R sold by the company Hoechst;
acrylic acidivinyl isodecanoate crosslinked copolymers such as the product Stabylen 30 sold by the company 3V;
acrylic acid/vinylpyrrolidonellauryl methacrylate terpolymers such as the products Acrylidone LM, ACP-1184 and ACP-1194 sold by the company ISP;
acrylic acid/lauryl (meth)acrylate copolymers such as the products Coatex SX sold by the company Coatex;
(meth)acrylic acid/alkyl acrylate/polyethoxylated alkyl allyl ether terpolymers such as the products Rheovis-CR, -CR3, -CR2 and -CRX sold by the company Allied Colloids;
methacrylic acidlethyl acrylate/polyethoxylated stearyl allyl ether terpolymers such as the products Salcare-SC90 and -SC80 sold by the company Allied Colloids (stearyl polyethoxylated with 10 mol of ethylene oxide, referred to as steareth-10);
methacrylic acid/ethyl acrylate/polyoxyethylenated lauryl acrylate terpolymers such as the product Rheo 2000 sold by Coatex;
methacrylic acid/ethyl acrylate/polyoxyethylenated stearyl methacrylate terpolymers such as the products Acrysol 22, Acrysol 25 and DW-1206A sold by the company Rxc3x6hm and Haas;
methacrylic acid/ethyl acrylate/polyoxyethylenated nonylphenyl acrylate copolymers such as the product Rheo 3000 sold by Coatex;
acrylic acid/polyoxyethylenated stearyl monoitaconate copolymers or acrylic acid/polyoxyethylenated cetyl monoitaconate copolymers such as the products 8069-72A and 8069-72B sold by National Starch;
methacrylic acid/butyl acrylate/hydrophobic monomer copolymers including a fatty chain, such as the product 8069-146A sold by National Starch;
acrylic acid/C15 alkyl acrylate/polyethylene glycol acrylate (28 mol of ethylene oxide) terpolymers such as the product Dapral GE 202 sold by the company Akzo;
salts of a partial fatty acid ester of an acrylic acid dimethylethanolamine/polymer, such as the product Dapral GE 202 DMA sold by the company Akzo;
copolymers of acrylic acid/acrylate/amphiphilic monomer including a fatty chain with urethane groups, such as the product Additol VXW 1312 sold by Hoechst;
acrylic polymers modified with hydrophobic groups containing a fatty chain, such as the product CS-0406 sold by Rxc3x6hm and Haas.
Depending on their nature, the polymers according to the invention may preferably be used in the form of aqueous solutions or in the form of aqueous dispersions.
It is possible to use, without discrimination, a film-forming polymer or a non-film-forming polymer, or even a mixture of film-forming and non-film-forming polymer.
In a preferred embodiment, the polymer according to the invention is thus a polymer in which the percentage and/or size of the hydrophobic groups are such that the hydrophobic groups are capable of combining, in aqueous medium, with other hydrophobic groups contained on the protein.
The proteins according to the invention are proteins including a hydrophobic group; the group may be naturally present in the protein, or may be added. The group may be quaternized or non-quaternized, and ionic or nonionic. In particular, mention may be made of proteins having, as a hydrophobic group, a fatty chain, for example an alkyl chain of 8-20 carbon atoms.
Mention may be made in particular, alone or as a mixture, of:
globular proteins: these are generally water-soluble proteins of reduced size, which in solution take the form of compact globules raning in size from 3 to 50 nanometers, among which mention may be made of:
albumins such as serum albumins (BSA), albumins extracted from egg white (ovalbumin) or albumins extracted from milk (lactalbumin).
certain enzymes such as lysozyme or proteases, in particular papain and trypsin.
globular proteins of plant origin, in particular wheat or soya proteins.
fibrous proteins: these are proteins which may become organized into long fibres, among which mention may be made of:
collagen and derivatives thereof such as tropocollagen and gelatin,
proteins of muscle structure such as elastin, or which constitute the structure of membranes, such as spectrin,
fibrous polymers of proteinic monomers having a low molecular mass, such as actin filament or fibrin.
proteins of unordered structure, with no tertiary structure, which in solution are in the form of random balls, among which mention may be made of caseins and mucins extracted from mucus (glycoproteins).
denatured proteins which can give aggregates resulting from the denaturation of a solution of lactalbumin, for example, or of various albumin solutions, or of casein solutions.
synthetic polypeptides having hydrophobic sequences, among which mention may be made of polypeptide homopolymers such as polylysine hydrochloride, and copolymers having polypeptide sequences or grafts.
Among the preferred proteins according to the invention, mention may be made of glycoproteins, which may be combined with mucopolysaccharides, or alternatively with papain, BSA or lysozyme which may be combined with radical polymers.
Mention may also be made of keratin or derivatives thereof, and hydrolysates of collagen, of proteins or of fibroin.
The proteins according to the invention may be in the form of aqueous solutions or optionally in the form of aqueous dispersions.
The combination according to the invention may in particular be used to thicken, or even to gel, aqueous media so as to obtain aqueous gels, for example. It may optionally be used within the context of the thickening of emulsions, in particular for surfactant-free emulsions, or for the thickening of aqueous dispersions.
Applications may thus be envisaged in particular in the fields of cosmetics, dermatology or hygiene, for the thickening in particular of cleansing gels or care gels for the skin or the hair, styling gels, antisun gels, make-up gels and buccodental gels.
An application may also be envisaged in the field of emulsions and in particular in oil-in-water emulsions, for example in care creams, cleansing creams or make-up creams for the skin or the hair, and antisun creams, or even hair creams.
The composition according to the invention preferably comprises less than 5% by weight of surfactant.
The amounts of protein and polymer to be added to an aqueous medium will be determined by those skilled in the art based on their general knowledge.
A representative composition is one in which the polymer is present in a concentration preferably ranging from 0.1 to 15% by weight, more preferably from 0.2 to 10%, by weight relative to the weight of the total polymer.
The amount of protein may preferably range from 0.005% to 0.2% by weight relative to the weight of the total polymer.
Preferably, the proteins are used in an amount such that a protein/polymer weight ratio ranging from 0.1:1 to 10:1 is obtained.
A thickened composition may thus be obtained, having a viscosity preferably ranging from 200 to 30,000 cp (mPa s), and comprising a very small amount of thickening agents, which may preferably range from about 0.8 to 3% by weight, relative to the total weight of the composition, for example.
Depending on the application envisaged, the composition may additionally comprise the usual constituents for this type of composition.
Mention may be made of any additive usually used in the field considered, such as pigments, fillers and/or pearlescent agents, antioxidants, fragrances, preserving agents, cosmetic or pharmaceutical active agents, moisturizers, vitamins, essential fatty acids, sunscreens, surfactants and self-tanning agents (for example DHA).
A person skilled in the art will of course take care to select this or these possible additional compounds, and/or their amount, such that the advantageous properties of the composition according to the invention are not, or are substantially not, adversely affected by the addition envisaged.